High resolution headline sonar cable

ABSTRACT

A production method for a headline sonar cable characterized by steps of:
         a. providing a first strength member ( 14 );   b. coupling to strength member ( 14 ) a conductor ( 122 );   c. forming a layer of polymeric material about the combination of strength member ( 14 ) and conductor ( 122 ) while ensuring that the conductor remains slack;   d. forming a flow shield around the layer of polymeric material, thus forming an elongatable internally located conductive structure; and   e. braiding a strength-member jacket layer ( 52 ) of polymeric material around the elongatable internally located conductive structure while ensuring that the conductor is slack when surrounded by the jacket layer ( 52 ).       

     For another embodiment, an optical fibre is wrapped around the exterior of the layer of polymeric material within which is enclosed a braided conductor formed about the first strength member ( 14 ). Other embodiments employ further thermo-plastic layers and further sheaths and further conductors.

TECHNICAL FIELD

The present disclosure relates generally to the technical field ofcables and, more particularly, to a cable that is made from a syntheticpolymeric material, that is resilient to crushing forces, that exhibitshigh stiffness and breaking strength, and that includes data signaland/or energy conductors therein.

BACKGROUND ART

A towed trawl usually includes a headline sonar sensor for monitoringthe trawl's headline height, the trawl's opening and fish schools infront of the trawl. A data transmission cable, i.e. a headline sonarcable that is sometimes called a third wire includes a conductor fortransferring data signals from the headline sonar sensor to the towingvessel. Presently, strength members of conventional headline sonarcables are made from steel, and enclose a central copper conductor thatis surrounded by layed, multi-layed and torsion balanced, or braidedcopper wires. The braided copper wires surrounding the central conductorshield the data signal carried on the central copper conductor fromelectromagnetic interference that degrades the quality of transmitteddata signals. Headline sonar cables can be up to 4000 meters long and,besides their main function of transferring data signals, the cable isalso sometimes used to increase trawl's opening by raising the headline.This is why a headline sonar cable is sometimes called a third wire.

When used with a trawl, a headline sonar cable must absorb the stressthat results from the trawler's surging on sea swells. Surging causesthe stern of the trawler where the third wire winch is located to impartsurging shocks to the headline sonar cable being deployed therefrom.Surging significantly increases compressive force applied to theheadline sonar cable at the winch thereby correspondingly increasing thelikelihood that the headline sonar cable's data signal conductor maybecome damaged.

One disadvantage of a conventional steel headline sonar cable is itsweight. The weight of a steel headline sonar cable adversely affectstrawl operation and fishing gear's performance. A long steel headlinesonar cable extending between a trawler and a trawl will, between thetrawler the headline sonar, descend below the trawl's headline.Furthermore, a trawler's headline sonar cable winch frequently lackssufficient power to tense the steel headline sonar cable since the winchis supporting the cable's weight.

A steel headline sonar cable that descends below the trawl's headlinenecessarily passes through schools of fish that are in front of thetrawl's opening. Passage of the steel headline sonar cable through aschool scares the fish and the school will turn sideways. A schools'sideways turn may reduce the catch because some of the fish avoid thetrawl's opening.

Another disadvantage of a steel headline sonar cable occurs if the cablebreaks. A broken steel headline sonar cable, due to its weight,initially falls downward and then starts cutting through and damagingthe trawl. Similarly, when the trawler turns while towing a trawl itoften becomes difficult to control a steel headline sonar cable to avoidcontact between the cable and the trawl's warp lines and/or the bridles.Contact between the headline sonar cable and the trawl's warp linesand/or bridles can damage either or both the headline sonar cable andthe trawl's warp lines and/or bridles. Similarly, sometimes a headlinesonar cable contacts a trawl door. Contact between a headline sonarcable and a trawl's door can result either in the cable being cut, orthe cable becoming entangled with the door so the trawl door becomeuncontrollable. Curing any of the preceding problems associated with theuse of a steel headline sonar cable requires retrieving, repairingand/or readjusting the fishing gear.

Over time rust also degrades a steel headline sonar cable. Furthermore,steel headline sonar cables are difficult to splice because theytypically consists of two twisted layers of steel wires, one layertwisted clockwise and the layer other counterclockwise.

Cables made from synthetic polymeric materials exhibit rather differentphysical properties compared to conductors, e.g. optical fibers andwires made from copper, aluminum or other metals. In general, theelasticity of conductors is very low while synthetic polymeric materialsgenerally exhibit greater inherent elasticity. Twisting stranding and/orbraiding fibers and/or filaments of synthetic polymeric materials into acable further increases elasticity of the finished cable due to voidsthat occur between fibers and/or filaments. A straight conductororiented parallel to or inside a cable made from synthetic polymericmaterials tends to break upon an initial application of tension whichstretches the cable. The constructional elasticity of cables made fromsynthetic polymeric materials can be reduced by stretching the cableeither while it is hot or cold. Stretching a cable made from syntheticpolymeric materials reduces elasticity by compressing the fibers and/orfilaments while also removing voids.

Fibers and/or filaments made from ultra high strength syntheticpolymeric materials like Ultra High Molecular Weight Polyethylene(“UHMWPE”), HMPE, Kevlar®, and Twaron® carbon fibers; aromaticpolyester, e.g. Vectran®; thermoset polyurethane. e.g. Zylon® andaromatic copolyamid, e.g. Technora®; typically have elongation to breakfrom 2-10%. A cable made from such materials generally exhibit 2-5%constructional elongation. If a conductor is placed inside or with acable made from such a synthetic polymeric material it must be able toaccept this elongation without either breaking or becoming brittle whichultimately results in premature conductor failure.

Tension bearing energy and data signal cables using synthetic fibers fora strength member are known. For example Cortland Cable Company offerssuch cables for seismic/magneto-meter tow cables, side-scan sonar andvideo tow cables and seismic ocean bottom cables. Such cables when usedfor tethering a remotely operated vehicle (“ROV”) operate at low tensionand insignificant surge. Strong surge shocks are unusual for currentapplications of ROV tether lines and moored ocean cables or the otheruses for known non-steel tension bearing energy and data signal cables.In fact, it is well known in the field that ROV's are not to be deployedwith such tether cables in surge conditions in which trawler's usuallyroutinely and actually operate.

In fact, it is accurate to state that when high tension is required incombination with repeated windings under tension onto a winch's drum andstorage under tension on that drum such as occurs with a trawl'sheadline sonar cable, it is not the predominant choice of the industryto form a tension bearing data signal cable having a conductor enclosedby a strength member formed of synthetic fibers. One of the reasons forthe industries continuing reliance on heavy, steel strength membereddata signal cables is that many past experiments at sheathing conductors(including fiber optic lines, copper wires, etc.) within strengthmembers such as braided jacket layers formed of synthetic polymericfibers have either failed in high tension applications, such as thosehigh tension applications described above, or have failed to provide alevel of resolution, that is a quality of the signal received, that issame or better as traditional constructions signal resolution.

WO 2004/020732 discloses a cable having a thermoplastic core enclosedwithin a braided, coextruded or pultruded jacket. During fabrication thecable is heated to a temperature at which the thermoplastic core becomesliquid or semiliquid. While heated to this temperature, the cable isstretched so it becomes permanently elongated. During stretching,material of the heated thermoplastic core fill voids within thesurrounding jacket. For added strength and/or stiffness, thethermoplastic core may include a central, inner strength member fiber orfilament that differs from that of the thermoplastic core and is madefrom a metal or polymeric material. Using the metal central innerstrength member to carry data signals doesn't work because during cablefabrication either the metallic wire either breaks or becomes so brittleas to fail prematurely.

In attempt to remedy the long felts needs in the industry applicant'sprior application WO 2009/142766 proposes a non-steel tension bearingdata signal and energy cable capable of tolerating very high loads suchas those applied to a trawl's headline sonar cable while also capable ofbeing wound on a drum or winch under high tensions and that can be woundand deployed from a winch subject to a fishing trawler's surging shockswhile not impairing the cable in a short time, especially in less thantwenty-four calendar months from a date of first use. While theseteachings have met with some acceptance in the industry, the needcontinues to improve the signal resolution, that is the quality of thedata signal received in the return loop for the headline sonar cable wepreviously proposed.

DISCLOSURE

An object of the present disclosure is to provide a non-steel headlinesonar cable capable of being wound on a winch under tensions and surgingshocks experienced by a fishing trawler that remains unimpairedthroughout a commercially practical interval of at least 24 calendarmonths from a date of first use, and more especially, that has a highersignal resolution than applicant's prior taught non-steel headline sonarcable described in WO 2009/142766.

Another object of the present disclosure is to provide a non-steelheadline sonar cable capable of being wound on a winch and remainingunimpaired under tensions and surging shocks experienced by, forexample, fishing trawlers and seismic vessels, particularly those havingdisplacements exceeding 100 tonnes and even exceeding 3000 tonnes.

Another object of the present disclosure is to provide a non-steelheadline sonar cable capable of being wound on a winch at a tensionexceeding 100 kg that remains unimpaired throughout a commerciallypractical interval of at least 24 calendar months from a date of firstuse on trawlers or seismic vessels exceeding 200 tonnes displacement.

Another object of the present invention is to provide a non-steelheadline sonar cable that does not kink when relaxed.

Disclosed is a method for producing a headline sonar cable having a highbreaking-strength and lighter weight than a conventional headline sonarcable having a strength member formed mainly or exclusively of steelwire. Most broadly, the method for producing the headline sonar cable ischaracterized by the steps of; a. providing an elongatableinternally-located conductive structure that is adapted for data signaltransmission and that includes at least one conductor; and b. braiding astrength-member jacket layer of polymeric material to enclose theelongatable internally-located conductive structure while ensuring thatthe elongatable internally-located conductive structure remainselongatable, i.e. is not full elongated, e.g. is slack, during the stepsof surrounding the elongatable internally-located conductive structurewith the strength-member jacket layer, and also, resultantly, whensurrounded by the strength-member jacket layer. Produced in this way,the elongatable internally-located conductive structure retains itsability to elongate during further desired processing steps, andespecially it does not break upon stretching of the strength-memberjacket layer surrounding the elongatable internally-located conductivestructure when stretching the strength member jacket layer under heat,especially heat over 80° C. to 145° C., and especially at tensions from7 to 35% and preferably 7 to 15% of the breaking strength of thepre-stretched strength member jacket layer, such heat-stretching beingdone so as to permanently elongate both the elongatableinternally-located conductive structure as well as the strength memberjacket layer simultaneous to one another, followed by simultaneouslypermitting to cool and/or cooling both the elongatableinternally-located conductive structure as well as the strength memberjacket layer, while maintaining a tension needed to retain the elongatedheadline sonar cable at a determined amount of elongation from itsinitial length, thereby permanently lengthening the headline sonar cablea predetermined amount while simultaneously not breaking or causing tobecome brittle the conductor.

In a preferred embodiment of the preceding method, the elongatableinternally-located conductive structure is formed by coupling aconductor 122 that is capable of data signal and/or electrical energytransmission to a first strength member 14 (preferably, such coupling iseffected prior to using the conductor for any other processing steps);and, subsequently coupling the combination of the electrical energyconductor 122 that is coupled to the first strength member 14 to a layer24 of thermoplastic material that is capable of reaching a molten phaseand that thus deforms during subsequent heat-stretching of thestrength-member jacket layer. Preferably, such coupling is accomplishedby enclosing the combination of the electrical energy conductor 122 thatis coupled to the first strength member 14 within the layer 24 ofthermoplastic material, such as may be accomplished by extruding and/orpultruding the layer of thermoplastic material about the combination ofthe electrical energy conductor 122 coupled to the first strength member14.

In one embodiment of the preceding method, the elongatableinternally-located conductive structure is formed by coupling anunstretched and/or elongatable braided conductor 122 that is capable ofdata signal and/or electrical energy transmission to a cord formed ofbraided fibers and/or filaments having, preferably but optionally, asoftening temperature that is higher than the softening temperature ofthe thermoplastic material. The electrical energy conductor 122 may beenclosed within a non-conductive braided sheath prior to and/or afterforming the layer 24 of thermoplastic around the combination of theconductor 122 and the first strength member 14 to which it is coupled.Or, alternatively, and presently preferred, the conductor 122 and thefirst strength member 14 to which it is coupled and the layer 24 ofthermoplastic that is formed around the combination of the conductor 122and the first strength member 14 to which it is coupled may be enclosedwithin a non-conductive braided sheath 32 after forming the layer 24 ofthermoplastic material around the conductor 122 and the first strengthmember 14. Preferably, the non-conductive sheath 32, also known hereinas a sheath layer 32, is formed by tightly braiding about and around theexterior surface of the layer 24 of thermoplastic material that isformed around the combination of the conductor 122 and the firststrength member 14 a hollow braided sheath of polyester fibers and/orfibers having a higher softening temperature (e.g. higher softeningpoint) in comparison to a softening temperature/softening point of thethermoplastic material forming the layer 24 of thermoplastic material.

Most preferably, and importantly, the braid angle selected when formingthe braided conductor is more obtuse in comparison to the braid angleselected for the initial formation with a braiding machine of thestrength-member jacket layer 52. The braid angle for the braidedconductor is selected so that the braided conductor can be elongated aminimum of four percent (4%) and preferably so that it can be elongatedby at least 14% without causing breakage of copper filaments forming thebraided conductor. These values are especially important when formingthe braided conductor with a hollow braided construction and whenenclosing the first strength member 14 within the hollow braidedconductor. Preferably, the step of enclosing the first strength member14 within the (preferably) hollow braided conductor is accomplished byfirst providing a strength member 14; and, secondly, by passing and/orfeeding the first strength member 14 through a braiding machine loadedwith filaments and/or fibers used to form the braided conductor, such asmay be copper filaments, and using the braiding machine to form a hollowbraided conductor 122 around and about a predetermined length of thefirst strength member 14.

For a metallic conductor or braided conductor, either of the precedingalternative embodiments includes further steps of:

1. after braiding the strength-member jacket layer 52 (not to beconfused with the first strength member 14) around the elongatableinternally-located conductive structure (that itself preferably includesa strength member 14):

-   -   a. heating the headline sonar cable; and    -   b. applying tension to the strength-member jacket layer so as to        permit stretching of the strength-member jacket layer sufficient        to elongate the headline sonar cable to cause a reduction in the        cross-sectional area of the strength-member jacket layer; and        2. while maintaining tension on the strength-member jacket        layer, cooling the headline sonar cable.

A tension is selected and a heat is selected so that not only dothermoplastic materials in the headline sonar cable become molten, andalso the material forming the strength-member jacket layer 52 becomesmore easily creeped without inducing failure, but the tension, heat, andtime period which the tension and heat are applied are selected so thata reduction in overall external diameter of the headline sonar cable offrom six percent to thirty-five percent, and more preferably of fromtwelve percent to twenty-five percent is attained from prior to thestretching step to after the stretching step.

Also disclosed is a non-steel headline sonar cable (meaning a headlinesonar cable having its primary load bearing strength member formedmainly and/or entirely of non-steel fibers) fabricated in accordancewith the disclosed method. An advantage of the disclosed non-steelheadline sonar cable is that it is lighter and has less density thanknown headline sonar cables having strength members formed exclusivelyof steel wires. Because the disclosed non-steel headline sonar cable islighter than, and correspondingly more buoyant in water than, aconventional steel headline sonar cable, the disclosed headline sonarcable is:

-   -   1. easier to handle and keep out of the trawl's path;    -   2. reduces the power required for trawler equipment that handles        the cable.    -   3. reduces the weight stored on winches aboard ship in        comparison to steel headline sonar cables, and thus reduces        forces destabilizing the vessel, thereby increasing safety.

Due to the disclosed headline sonar cable's low weight and buoyancy, itspath from a trawler's winch down to the trawl's headline is more direct.Furthermore, due both to the disclosed headline sonar cable's low weightand to the trawl's towing speed, the disclosed headline sonar cabletends to remain above the trawl's headline rather than descending belowthe headline. If a headline sonar cable remains above the trawl'sheadline, it cannot contact the trawl's warp lines, bridles and/ordoors. Furthermore, if such a headline sonar cable breaks it will floatover the trawl thereby avoiding damage to the trawl.

Another advantage of the disclosed non-steel headline sonar cable isthat it can be spliced more easily and more quickly than a conventionalsteel headline sonar cable.

Yet another advantage of the disclosed non-steel headline sonar cable isthat it corrodes less than a conventional steel headline sonar cable.Consequently, the disclosed non-steel headline sonar cable will lastlonger than a conventional steel headline sonar cable.

Yet another advantage of the disclosed non-steel headline sonar cable isthat it exhibits less heat fatigue than a conventional steel headlinesonar cable.

Possessing the preceding advantages, the disclosed non-steel headlinesonar cable answers needs long felt in the industry.

These and other features, objects and advantages will be understood orapparent to those of ordinary skill in the art from the followingdetailed description of the preferred embodiment as illustrated in thevarious drawing figures.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view of a headline sonar cable in accordance with thepresent disclosure that reveals various layers included in oneembodiment thereof;

FIG. 1A is a cross-sectional view that depicts those layers of theheadline sonar cable which appear at the line 1A-1A in FIG. 1 as thoselayers appear in the finished headline sonar cable;

FIG. 2 is a plan view illustrating a fiber optic conductor such as maybe a coaxial cable that is capable of data transmission wrapped around alayer of thermoplastic material that both deforms during subsequenttensioning of an enclosing strength-member jacket layer and that alsoencloses at least one electrical energy conductor, all of which areincluded in the headline sonar cable depicted in FIG. 1;

FIG. 2A is a cross-sectional view showing the deformable layer ofthermoplastic material with the data transmission conductor wrappedtherearound and the at least one electrical energy conductor containedtherein, taken along the line 2A-2A in FIG. 2;

FIG. 3 is a plan view illustrating the fiber optic conductor wrapped ina spiral around the thermoplastic layer of the headline sonar cabledepicted in FIG. 2 after being enclosed within a sheath layer ofmaterial that has a higher softening temperature than that of thethermoplastic layer;

FIG. 3A is a cross-sectional view of the fiber optic conductor; thethermoplastic layer, and the electrical energy conductor containedwithin the thermoplastic layer, of FIG. 2, all enclosed within thesheath layer, that is taken along the line 3A-3A in FIG. 3;

FIG. 4 is a plan view illustrating the fiber optic conductor; thethermoplastic layer; the electrical energy conductor contained withinthe thermoplastic layer; and the sheath layer of the headline sonarcable depicted in FIG. 3, all after being enclosed within a shieldinglayer of electrically conductive material;

FIG. 4A is a cross-sectional view of the fiber optic conductor; thethermoplastic layer; the electrical energy conductor enclosed within thethermoplastic layer; and the sheath layer, all of FIG. 3, all enclosedwithin the shielding layer that is taken along the line 4A-4A in FIG. 4;

FIG. 5 is a plan view illustrating the fiber optic conductor; thethermoplastic layer; the electrical energy conductor contained withinthe thermoplastic layer; the sheath layer; and the shielding layer ofthe headline sonar cable depicted in FIG. 4, all after being enclosedwithin an optional water-barrier layer of material;

FIG. 5A is a cross-sectional view of the fiber optic conductor, thethermoplastic layer; the electrical energy conductor enclosed within thethermoplastic layer; the sheath layer; and the shielding layer of FIG.4, all enclosed within the water-barrier layer that is taken along theline 5A-5A in FIG. 5;

FIG. 6 is a plan view illustrating the fiber optic conductor; thethermoplastic layer; the electrical energy conductor enclosed within thethermoplastic layer; the sheath layer; the shielding layer; and thewater-barrier layer of the headline sonar cable depicted in FIG. 5, allafter being enclosed within an extrusion-barrier layer of material;

FIG. 6A is a cross-sectional view of the fiber conductor; thethermoplastic layer; the electrical energy conductor enclosed within thethermoplastic layer; the sheath layer; the shielding layer; and thewater-barrier layer of FIG. 5, all enclosed within the extrusion-barrierlayer that is taken along the line 6A-6A in FIG. 6;

FIG. 7 is a plan view illustrating the fiber optic conductor; thethermoplastic layer; the electrical energy conductor enclosed within thethermoplastic layer; the sheath layer; the shielding layer; thewater-barrier layer; and the extrusion-barrier layer of the headlinesonar cable, depicted in FIG. 6, all after being enclosed within thestrength-member jacket layer of polymeric material;

FIG. 7A is a cross-sectional view of the fiber optic conductor; thethermoplastic layer; the electrical energy conductor enclosed within thethermoplastic layer; the sheath layer; the shielding layer; thewater-barrier layer; and the extrusion-barrier layer, of FIG. 6, allenclosed within the strength-member jacket layer that is taken along theline 7A-7A in FIG. 7;

FIG. 8 is a plan view illustrating the fiber optic conductor; thethermoplastic layer; the electrical energy conductor enclosed within thethermoplastic layer; the sheath layer; the shielding layer; thewater-barrier layer; the extrusion-barrier layer; and thestrength-member jacket layer of the headline sonar cable, depicted inFIG. 7, all after being enclosed within a protective layer of material;

FIG. 8A is a cross-sectional view of the fiber optic conductor; thethermoplastic layer; the electrical energy conductor enclosed within thethermoplastic layer; the sheath layer; the shielding layer; thewater-barrier layer; the extrusion-barrier layer; and thestrength-member jacket layer, of FIG. 7, all enclosed within theprotective layer that is taken along the line 8A-8A in FIG. 8;

FIG. 9 is a plan view of a portion of an alternative embodiment for anelongatable centrally-located conductive structure included in a mostpreferred alternative embodiment of the headline sonar cable depicted inFIGS. 1, 1A, 2-8 and 2A-8A, and lacking the fiber optic conductorspiraling around the layer of thermoplastic material enclosing theelectrical energy conductor;

FIG. 9A is a cross-sectional view that depicts those layers of thealternative embodiment headline sonar cable which appear at the line9A-9A in FIG. 9 as those layers appear in the finished headline sonarcable.

BEST MODE FOR CARRYING OUT THE DISCLOSURE

FIG. 1 illustrates a headline sonar cable in accordance with the presentdisclosure that is identified by the general reference character 20.FIG. 1 depicts a preferably insulated electrical conductor 122 coupledto a first strength member 14, the combination of the electricalconductor 122 and the first strength member 14 enclosed within a layer24 of deformable material. A fiber optic conductor 22 is wrapped inspiral form around the layer of deformable material and therefore aswell is wrapped around the combination of the electrical energyconductor 122 coupled to the first strength member 14, as these arecontained within the layer 24 of deformable material. The layer 24 ofdeformable material enclosing the combination of the electrical energyconductor 122 coupled to the first strength member 14, and the fiberoptic conductor 22 wrapped in spiral form around the layer 24 ofdeformable material, all being enclosed within a sequence of layersincluded in the particular embodiment of the headline sonar cable 20illustrated in FIG. 1. The steps of a first fabrication method describedbelow assemble the headline sonar cable 20 depicted in FIG. 1.

The First Fabrication Method:

Step (1)

Fabrication of the headline sonar cable 20 depicted in FIG. 1 beginswith coupling an electrical conductor 122 to a first strength member 14.Next, a layer 24 of deformable material is formed about the combinationof the electrical conductor 122 coupled to the first strength member 14.The layer 24 of deformable material preferably is a thermoplasticmaterial, such as Polyethylene, such as cellular Polyethylene. Thepreferred method of coupling the electrical conductor 122 to the firststrength member 14 is to form the electrical conductor at the moment itis being coupled to the first strength member 14. A preferred method toaccomplish this is to braid an electrical energy conductor about thefirst strength member 14. A useful first strength member 14 for thisprocess is a braided twine or cord, that can be made of synthetic ornatural filaments. A parallel lay or twisted lay twine or cord also isuseful, as is a single monofilament of a circular cross sectional form,though almost any cross sectional form is useful. A preferred propertyfor the first strength member 14 is that it has less ability to elongatethan does the electrical conductor, especially at temperatures lesserthan 50° C., such as at 20° C. Most preferably, the first strengthmember 14 has a range of elongation measured at 5 kg tension and at 20°C. that is from no elongation up to a maximum of 3% elongation.

After forming the structure that includes the combination of theelectrical energy conductor 122 coupled to the first strength member 14where the electrical energy conductor 122 and the first strength member14 are enclosed within a layer of thermoplastic material, an optionalstep in the fabrication process, that is used when making one preferredembodiment of the present disclosure, is to wrap at least one fiberoptic cable in spiral form around the exterior of the thermoplasticlayer, as depicted in greater detail in FIGS. 2 and 2A. The deformablematerial of the layer 24 can be a thermoplastic material, a plasticmaterial, or any other material that deforms when exposed to pressuresgenerated while stretching various layers of the headline sonar cable 20depicted in FIG. 1 in the manner described in greater detail below.

An essential characteristic of the present disclosure is that allsubsequent processing steps including a step of stretching variouslayers of the headline sonar cable 20 depicted In FIG. 1 preserves theintegrity of the electrical energy conductor 122, and, in the case whereit has been chosen to include the at least one fiber optic conductor 22,also preserves the integrity of the at least one fiber optic conductor22.

Regarding the fiber optic conductor 22 and/or the electrical energyconductor 122, any insulation thereon: 1. has a higher softeningtemperature than that of the preferably thermoplastic layer 24; while 2.being deformable during stretching various layers of the headline sonarcable 20 in the manner described in greater detail below. There existnumerous conventional insulating materials that satisfy the precedingcriteria for an insulator included in the headline sonar cable 20.

The fiber optic conductor can be a coaxial cable. The shape of the fiberoptic conductor 22 when twisted and/or wrapped around the layer 24 isthat of a spiral, although in accordance with the present disclosure thefiber optic conductor may be twisted and/or wrapped around the layer 24in shapes other than that of a spiral or helix which alternative shapesalso function as well in the headline sonar cable 20 as the spiralshape. In fact, any suitably arranged configuration for the headlinesonar cable 20 in which the fiber optic conductor 22 meanders along thelength of the layer 24 should be capable of providing sufficient slackso that it does not break while stretching various layers of theheadline sonar cable 20 depicted in FIG. 1 in the manner described ingreater detail below.

The conductive material of the headline sonar cable 20 includes fibersand/or filaments for carrying information. In accordance with thepresent disclosure such information carrying fibers and/or filamentsinclude optical fibers and electrically conductive wire. Usually, theheadline sonar cable 20 includes filaments capable of carryingelectrical energy and/or current, such as copper strands or wires. Forpurposes of this disclosure, the terms fiber and filament are usedinterchangeably.

Step (2)

Referring now to FIGS. 3 and 3A, the next step in forming the headlinesonar cable 20 is enclosing (including forming a sheath 32 over):selected embodiment of the headline sonar cable of the presentdisclosure, selected from a group consisting of:

-   -   I) the deformable layer 24 enclosing the combination of the        electrical energy conductor 122 coupled to the first strength        member 14; or    -   II) the combination of the at least one fiber optic conductor 22        spiraled around the layer 24 enclosing the combination of the        electrical energy conductor 122 coupled to the first strength        member 14.

Preferably, the structures described in Step (2), (I) and (II)immediately above are enclosed within a sheath layer 32 of material thathas a higher softening temperature than that of the layer 24. If tightlybraided, wrapped or extruded material of the sheath layer 32 has ahigher softening temperature than the material of layer 24, the materialof the layer 24 does not extrude or mainly does not extrude through thesheath layer 32 during prestretching and/or heat setting most of thecable layers depicted in FIG. 1 in the manner described in greaterdetail below. The sheath layer 32 may be formed by tightly braidingpolyester fibers, having a higher softening temperature than that of thelayer 24, about the layer 24 containing the combination of theelectrical energy conductor 122 coupled to the first strength member 14,as in Step (2) (I) above; or, alternatively, the sheath layer 32 may beformed about the combination of the at least one fiber optic conductor22 spiraled around the layer 24 containing the combination of theelectrical energy conductor 122 coupled to the first strength member 14,as in Step (2) (II) above, both alternatives forming alternativeembodiments of a preferred elongatable internally-located conductivestructure 34 of the headline sonar cable 20.

Step (3)

Referring now to FIGS. 4 and 4A, the next step in forming the headlinesonar cable 20 is overbraiding or overtwisting about the sheath layer 32of FIG. 3, and all contained within it, with a shielding layer 36 ofelectrically conductive material, e.g., copper wires, to shield at leastthe electrical conductor 122 from electromagnet interference. Theshielding layer 36 must remain unimpaired when elongating up to fourteenpercent (14%) and even up to nineteen percent (19%) while stretchingvarious layers of the headline sonar cable 20 depicted in FIG. 1 in themanner described in greater detail below.

Step (4)

Referring now to FIGS. 5 and 5A, the next step in forming the headlinesonar cable 20 is to pultrude or extrude, cover or otherwise enclose(including forming a sheath over) the shielding layer 36, and allcontained within it, with a water-barrier layer 42 to serve as a watershield. Preferably polyethylene forms the water-barrier layer 42.Preferably, and contrary to the state of the art and the teachings inthe industry, the water barrier layer is formed with greater thicknessthan minimally required for a water barrier layer, and preferably with athickness and/or a material volume that is greater than the materialvolume used in forming the layer 24 of thermoplastic material; and/or,preferably also, and contrary to the state of the art and the teachingsin the industry, the water barrier layer is formed both with greaterthickness than minimally required for a water barrier layer, andpreferably with a volume of material that is greater than a volume ofmaterial of any fiber optic conductor 22 used in the headline sonarcable 20 of the present disclosure, including greater than the volume ofany coaxial cable used for the fiber optic conductor 22.

Step (5)

Referring now to FIGS. 6 and 6A, the next step in forming the headlinesonar cable 20 is to overbraid or cover the water-barrier layer 42 andall that is contained within it with a tightly braided or wrappedextrusion-barrier layer 46 of a material having a higher softeningtemperature than the material of the water-barrier layer 42. If tightlybraided, wrapped or extruded material of the extrusion-barrier layer 46has a higher softening temperature than the material of thewater-barrier layer 42, the material of the water-barrier layer 42 doesnot and/or mainly does not extrude through the extrusion-barrier layer46 during prestretching and/or heat setting most of the cable layersdepicted in FIG. 1 in the manner described in greater detail below. Forexample, the extrusion-barrier layer 46 may be formed from braidedpolyester fibers (including plaits, strands and filaments and other).

Step (6)

Whatever combination of layers are included in the headline sonar cable20, the next step in forming the headline sonar cable 20 is tooverbraided over all those layers with a layer of polymeric fiber suchas UHMWPE, HMPE, Aramids (Kevlar), carbon fibers, LCP (Vectran), PBO(Zylon), Twaron and Technora, etc. to form the strength-member jacketlayer 52 of the headline sonar cable 20.

Step (7)

A predetermined tension is now applied to the strength member jacketlayer 52, and thus by extension to all it contains, including but notlimited to: the first strength member 14; the electrical conductor 122,the deformable layer 24; the sheath layer 32; the shielding layer 36;the water barrier 42; the extrusion-barrier layer 46. Thestrength-member jacket layer 52, together with any other layers enclosedwithin the strength-member jacket layer 52, and the strength-memberjacket layer 52 itself, are then heat-stretched in such a way as tocause the layer 24 and the water barrier 42 as well as any otherthermoplastic layers to become malleable (semi-soft) and most preferablyto become molten (“semi-liquid”) so these layers and any otherthermoplastic layers can be permanently deformed, and otherwise in sucha way as described below. A key determining factor for the predeterminedtension is to use a tension that applies a load to at least thestrength-member jacket layer 52, prior to applying the heat that causesthermoplastic materials in the headline sonar cable to become molten,that stops the fibers and/or filaments forming the strength-memberjacket layer 52 from looing their strength upon application of the heat,or mainly stops them from losing strength upon application of the heat.

Step (8)

The headline sonar cable 20 preferably is heated to a temperature thatcauses the deformable layer 24 and other thermoplastic layers to becomeboth malleable and moldable, for example, especially molten(semi-liquid) so they become permanently deformable but not so hot thattheir thermoplastic material is liquid. While maintaining the headlinesonar cable 20 in this heated state, fabrication of the headline sonarcable 20 concludes with performing the operations described in Stepsbelow.

Step (9)

The next fabrication step is stretching the headline sonar cable 20applying sufficient tension to at least the strength-member jacket layer52 so as to elongate the strength-member jacket layer 52 a desiredamount. The desired amount of elongation of the strength-member jacketlayer 52 is usually an amount that after the headline sonar cable 20cools the strength-member jacket layer 52 is unable to stretch more thanapproximately three and one-half percent (3.5%) until breaking, and morepreferably so that it is unable to stretch more than half a percent(0.5%) until breaking, and especially so as to permit permanentelongation of the cooled jacket layer.

The heat and tension are selected so that fibers and/or filamentsforming the strength-member jacket layer 52 are also permanentlyelongated. The permanent elongation of the fibers and/or filamentsforming the strength-member jacket layer 52 is preferably to an extentthat loads applied to the headline sonar cable are also applied to allthe fibers and/or filaments forming the strength-member jacket layer.

A preferred temperature when stretching the headline sonar cable 20 whenthe strength-member jacket layer 52 is formed of UHMWPE is 117° C. Atemperature between 114° C. to 117° C. is highly useful. A temperaturebetween 110° C. to 120° C. is useful, with a temperature range 100° C.to 124° C. also being useful. Depending upon the tension applied to thestrength-member jacket layer 52 of the headline sonar cable 20, and alsodepending upon the types of fibers and/or filaments used in making theheadline sonar cable 20, temperatures from 90° C. to 150° C. are useful.

In general, applying more tension to the headline sonar cable 20 reducesthe temperature to which the headline sonar cable 20 must be heated, andconversely. The temperature selected and applied and the tensionselected and applied are such as to maximize the strength of the jacketlayer in the headline sonar cable 20 while also minimizing, andpreferably eliminating, its ability to further elongate;

Step (10)

The final fabrication step is cooling the headline sonar cable 20 whilemaintaining tension on at least the strength-member jacket layer 52 sothat it together with the other layers cool while under tension. In thisway: 1. all layers of the headline sonar cable 20 become permanentlyelongated while also becoming permanently formed into a position andacquiring a shape that supports the internal shape of the tensestrength-member jacket layer 52, especially when the strength-memberjacket layer 52 is formed with a hollow-braid construction. For example,as a result of this last step, the fiber optic conductor 22, when used,becomes compressed against the malleable layer 24, and as a resultdisplaces some of the layer 24 and actually comes to occupy some of thespace formerly occupied only by the layer 24. Due to elongation of theheadline sonar cable 20, the diameter in which the fiber opticconductor(s) 22 is/are initially wrapped around the layer 24 shrinkswith and becomes embedded within the deformable and preferablythermoplastic layer 24. Depending upon how much tension is applied tothe headline sonar cable 20 during fabrication, the combined fiber opticconductor(s) 22 and layer 24 and, often, the water barrier 42 can becomepressed against one another to an extent that spaces between these itemsare often barely discernable or are not discernable.

Due to the heating and stretching described above all layers of theheadline sonar cable 20 enclosed within the strength-member jacket layer52 and the strength-member jacket layer 52 assume a shape that supportsand conforms to the internal wall of the immediately surrounding layer.Accordingly, during heating and stretching of the headline sonar cable20 the extrusion-barrier layer 46, when used, as is in some embodimentsoptional as the layer 24 may serve as an extrusion barrier layer for theelectrical conductor(s) 122, directly contacting the strength-memberjacket layer 52 takes a shape that supports and conforms precisely tothe internal shape of the strength-member jacket layer 52. Layers of thefinished headline sonar cable enclosed within the extrusion-barrierlayer 46 assume a shape similar to that of the extrusion-barrier layer46 with the degree of similarity decreasing progressively toward thecenter of the headline sonar cable 20.

Step (11)

Lastly, referring to FIG. 8, a cover may be applied to the headlinesonar cable 20 by over-braiding or cover-braiding the strength-memberjacket layer 52 and everything enclosed within the strength-memberjacket layer 52 with a final protective layer 56 of the headline sonarcable 20. The protective layer 56 shields the strength member fromdamage caused by abrasion or cutting and exposure to chemicals and theelements. HMPW and UHMWPE fibers formed into yarns are especiallyuseful, and can be blended with fibers having higher coefficients offriction than does HMPE or UHMPE to form yarns used for forming acoverbraid over the strength-member jacket layer 52. The cover layer 56preferably is adhered to the strength-member jacket layer 52 by having ahighly elastic and highly resilient adhesive substance situated onto theexterior surface of the strength-member jacket layer 52 prior to andbest immediately prior to braided about it the cover layer 56,especially elastic substances having a higher shear strength when set(i.e. “cured”) than does silicone.

Preferred Alternative Fabrication Method

FIGS. 9 and 9A and depict a most preferred, alternative embodimentheadline sonar cable in accordance with the present disclosure thatlacks a fiber optic conductor formed in spiral about a thermoplasticlayer enclosing an electrical conductor 122, and is identified by thegeneral reference character 120. Those elements depicted in FIGS. 9 and9A that are common to the headline sonar cable 20 illustrated in FIGS.1-8, 1A, and 2A-8A carry the same reference numeral distinguished by aprime (“′”) designation. The most preferred embodiment of the headlinesonar cable 120 depicted in FIGS. 9 and 9A eliminates the at least onefiber optic conductor 22 formed in a spiral exterior the thermoplasticlayer 24 that is exterior the electrical conductor 122 from theelongatable internally-located conductive structure 34. Instead, theheadline sonar cable 120 includes an initially unstretched braidedelectrical conductor 122 that has a polymeric layer formed around itsuch as by extruding or pultruding a polymeric thermoplastic layer 124around the braided conductor 122. A non-conductive braided sheath 132 isformed about the polymeric layer 124, and preferably is overbraidedaround the polymeric layer 124. Preferably, the braided sheath 132 isformed of fibers such as polyester fibers. The polymeric layer 124 ispreferably formed from cellular polyethylene and has a radial thicknessthat establishes a proper electrical impedance for the headline sonarcable 120. The use of cellular polyethylene for electrical insulation isfurther described at least in U.S. Pat. Nos. 4,173,690, 5,346,926 and7,507,909 B2 that are hereby incorporated by reference. Alternatively, apolyurethane material may also be used provided that it does not tend tocontract the headline sonar cable 20 longitudinally after stretchingvarious layers of the headline sonar cable 20 depicted in FIG. 1 in themanner described in greater detail below.

Configured as described above, the braided conductor 122 formed aboutthe first strength member 14, the polymeric layer 124 formed about thebraided conductor, and the braided sheath 132 formed about the polymericlayer 124, together form a most preferred embodiment of an elongatableinternally-located conductive structure 134 of the headline sonar cable120. After the elongatable internally-located conductive structure 134has been assembled, fabrication of the most preferred, alternativeembodiment headline sonar cable 120 then continues with furtherprocessing the elongatable internally-located conductive structure 134as described previously for Steps (3) through (11) above.

Alternative configurations of the elongatable internally-locatedconductive structure for alternative preferred embodiments of theheadline sonar cable

Alternatively, as shown in FIG. 10 and FIG. 11, that show alternativepreferred embodiments of the headline sonar cable 220 and 320,respectively, disclosed is an alternative configuration for anotherpreferred embodiment of the elongatable internally-located conductivestructure 134 x, that may be used individually in the headline sonarcable, or in severality, or both individually and/or in severality inconjunction with other embodiments of the elongatable internally-locatedconductive structure.

-   -   The alternative preferred elongatable internally-located        conductive structure 134 x includes: the braided conductor 122        formed about the first strength member 14; the thermoplastic        layer 124 formed about the braided conductor 122; a layer of        electrically conductive material 36 x that preferably is laid or        braided copper filaments our is a double layer of torque        balanced layed copper filaments in S and Z configuration (e.g.        each of the two layers is opposite in lay from the other) is        formed about the thermoplastic layer 124; another layer of        thermoplastic material 124 x is formed about the layer of        electrically conductive material 36 x; and a tightly braided        sheath 132 x formed preferably of polyester fibers having a        higher softening point than that of both thermoplastic layers        124 and 124 x is formed about the another thermoplastic layer        124 x. A preferred material for forming the thermoplastic layers        124 and 124 x is cellular polyethylene.

Further Preferred Embodiments Using Alternative Configurations of theElongatable Internally-Located Conductive Structure

In further reference to FIG. 10, an alternative headline sonar cable 220is shown where multiple conductive power conductors 125 are combinedwith an alternative enlongatable internally-located conducive structure134 x of the present disclosure in order to form an alternative headlinesonar cable 220 of the present disclosure. To form the multiple powerconductors 125, most preferably: several distinct hollow braidedconductors 122 with a first strength member 14 (not shown with allconductors 122 to prevent cluttering the drawing) internal the hollowbraided conductor 122 are formed as taught herein and above; secondly alayer of thermoplastic material 124 y is extruded and/or pultruded orotherwise formed about each conductor 122 so as to form a sheath layer124 y of thermoplastic material surrounding a length of hollow braidedconductor 122, thereby forming a bar 126. Next, several distinct andindividual lengths of such bars 126 are provided and assembled into abundle 127, preferably in parallel lay configuration, where the bundle127 has at its core an alternative elongatable internally-locatedconductive structure 134 x. The position of the elongatableinternally-located conductive structure 134 x as shown in FIG. 10, thathas been described as at “the core” of the bundle 127, can alsooptionally be described as being disposed coaxial with the long axis ofthe headline sonar cable relative to the multiple distinct additionalelectrical energy conductors 122 as well as relative to the multiplebars 126 and as well relative to the bundle 127. Next, the bundle 127 isretained in the bundle's configuration, either by being wound about byusing tape or by being otherwise bound. Next, a sheath 132 y of tightlybraided material, such as polyester fibers, that is capable of retainingmolten phases of the thermoplastic material forming the bars 126 is thenformed about the bundle 127. The sheath 132 y can be formed as a singlelayer, or as a two or more layered sheath, shown in FIG. 10 is a twolayered sheath 132 y. The remainder of the processing steps, startingwith forming the strength-member jacket layer 52 about the sheath 132 y,continues as described previously for Steps (3) through (11) above toform the alternative headline sonar cable 220.

-   -   Alternatively again, by eliminating the internally-located        conductive structure 134 x from the bundle, a Powerable Warp or        Powerable Cable 320 is formed, see FIG. 11. Powerable Cable 320        is not ideal for information transmitting capability, but is a        power transmitting cable having a synthetic strength member that        is capable of tolerating crushing forces on high tension drums.        A polyurethane layer situated between and adhering together the        sheath and the strength member jacket layer is useful in all        embodiments of the headline sonar cable 20, 120, 220, 320 and        420 (see FIG. 12), and is indicated in FIG. 11 by reference        numeral 130.

In headline sonar cable 220 the primary use for the conductor 122located within the alternative elongatable internally-located conductivestructure 134 x is delivery of data signals. However, the primary usefor the conductors 122 located within the bars 126 is delivery of power.A preferred minimum quantity of bars 126 forming the bundle 127 of(preferably parallel laid) bars is at least three, with at least six toeight bars being presently preferred. More bars can be used, up tothousands. The use of a first strength member 14 with each of thebraided conductors contained within each of the bars in the manner astaught herein and above is preferred. A useful construction method forforming the bars and resultant structure is to first provide multipledistinct first strength members 14; then to form around each distinctfirst strength member 14 a braided conductor 122 preferably as a hollowbraided conductor, preferably of copper filaments. Next, to pass each ofthe braided conductors 122 through an extrusion or pulltrusion devisethat extrudes and/or pultrudes about each of the braided conductors 122a layer of thermoplastic material, thus forming an above described bar126.

In reference to FIG. 12: An alternative headline sonar cable 420 isformed by, in substitution of the bars described above, several distinctalternative elongatable internally-located conductive structures 134 xare arranged into an alternative bundle 128, with or without a centrallylocated elongatable internally-located conductive structure 134 xinterior the bundle (no such centrally located elongatableinternally-located conductive structure 134 x being shown in the exampleof a headline sonar cable 420 as shown in FIG. 12). Next, another layer124 z of thermoplastic material is formed about the bundle. Next,another flow shield 132 z of tightly braided fibers that preferably arepolyester fibers is formed about the another layer 124 z ofthermoplastic material. The remainder of the headline sonar cable'sstructures are then formed around the flow shield 132 z that enclosesthe bundle and the headline sonar cable is further processed asdescribed previously for Steps (3) through (11) above. This preferredembodiment of headline sonar cable 320 is useful for transmission bothof power as well as of data.

INDUSTRIAL APPLICABILITY

A headline sonar cable of the present disclosure also is capable ofbeing used as a trawler warp, a towing warp, a deep sea winch line, acrane rope, a seismic line, a deep sea mooring line, a well bore line,and ROV tether or ROV line, a superwide for seismic surveillance, or asa load bearing data and/or energy cable. When the headline sonar cable20 is fabricated for certain applications, such as headline cables usedfor towed seismic surveillance arrays, the headline sonar cable 20 mayinclude several individual elongatable internally-located conductivestructures 134; and/or may include several individual optical or otherinformation carrying fibers and/or filaments rather than a singleoptical or other fiber and/or filament as depicted in the illustrationof FIGS. 1A and 2A. For the purposes of this disclosure, as manydistinct conductive optical and/or other fibers and/or filaments asrequired to carry both data signals and electrical energy for anyparticular application are understood to be included in the headlinesonar cable 20, whether there be one or hundreds or even more distinctinformation carrying fibers and/or filaments. As is readily apparent tothose skilled in the art, for a headline sonar cable 20 having two (2)or more distinct information carrying electrically conductive fibersand/or filaments each of those fibers and/or filaments must beelectrically insulated from all of the other distinct informationcarrying fibers and/or filaments.

Moreover, it is a most preferred embodiment that a headline sonar cable120 of the type depicted in FIGS. 9 and 9A having the single braidedconductor 122 or the headline sonar cable 20 of the type depicted inFIGS. 1A and 2A having the combination of the single braided conductor122 and the single fiber optic conductor 22 may include severalindividual conductors 122 in place of the single conductor 122, and myinclude several individual fiber optic conductors 22, that may be formedof traditional coaxial cables, where each individual electrical energyconductor 122 is formed of multiple information and/or energy carryingfibers and/or filaments, for example multiple copper filaments. For thepurposes of this disclosure, as many distinct conductive fibers and/orfilaments as required to carry both data signals and/or electricalenergy for any particular application are understood to be included ineach of the multiple conductors 122 that are situated in the headlinesonar cable in substitution of the single conductor 122, whether therebe one or hundreds or even more distinct information carrying fibersand/or filaments forming each individual conductor 122. Each conductor122, formed of multiple information and/or energy carrying fibers and/orfilaments, is preferably formed with a braided construction. The term“braided construction” is understood to include “plaited construction”.The presently preferred construction for each of such multiple distinctand individual conductors 122 is a “hollow braid” or “hollow braided”construction, the terms “hollow braid” and “hollow braided” referring tothe same structure.

In addition to being used with trawls, headline sonar cables inaccordance with the present disclosure may be used as synthetic towingwarps on trawlers or other vessels, are also used as a lead-in cable fortowed seismic surveillance arrays, or a towing warp, a deep sea winchline, a crane rope, a seismic line, a deep sea mooring line, a well boreline, and ROV tether or ROV line, a superwide for seismic surveillance,or as a load bearing data and/or energy cable. Towing seismicsurveillance arrays requires that the lead-in cable transmit bothelectrical energy and data signals a long distance between the towingvessel and the array with a minimum of drag, a minimum of weight, and aminimum of lead-in cable movement.

Furthermore, a significant use for headline sonar cables is stationaryseismic surveillance such as anchored and/or moored cables fortransmitting both data and electrical energy, and requiring a certainstrength. Stationary seismic cables transfer data signals often up to asurface buoy, and are positioned on and/or relative to the seabed forlong periods of time, even several years. Ocean currents tend to movesuch anchored seismic cables. Because it is important to limit movementof an anchored seismic cable as much as practicable, it is advantageousto reduce as much as possible the effect of ocean currents on ananchored seismic cable's location. A thinner anchored seismic cabletends to be moved less by ocean currents. Although the present inventionhas been described in terms of the presently preferred embodiment, it isto be understood that such disclosure is purely illustrative and is notto be interpreted as limiting. Consequently, without departing from thespirit and scope of the disclosure, various alterations, modifications,and/or alternative applications of the disclosure will, no doubt, besuggested to those skilled in the art after having read the precedingdisclosure. Accordingly, it is intended that the following examples beinterpreted as encompassing all alterations, modifications, oralternative applications as fall within the true spirit and scope of thedisclosure.

1-196. (canceled)
 197. A method for producing a headline sonar cable(20, 120, 220, 320, 420), comprising the steps of: a. providing a firststrength member (14); b. providing a conductor (122) that is capable ofdata signal and/or electrical energy transmission and is capable ofelongation; c. forming an elongatable internally located conductivestructure by: i. coupling said conductor (122) to said first strengthmember (14) while ensuring that the conductor remains able to elongate;ii. coupling the combination of the electrical energy conductor (122)and the first strength member (14) to thermoplastic material that iscapable of reaching a molten phase and deforming during subsequentheating; d. braiding a strength-member jacket layer (52) of polymericmaterial so as to enclose the elongatable internally-located conductivestructure while ensuring that the conductor remains elongatable duringthe steps of surrounding the elongatable internally-located conductivestructure with the strength-member jacket layer (52) so that theconductor retains its ability to elongate during further desiredprocessing steps and does not break upon stretching under heat andtension of the strength-member jacket layer (52) surrounding theelongatable internally-located conductive structure, wherein the firststrength member (14) and strength-member layer (52) are selected andformed so that said first strength member (14) has less breakingstrength than the strength member jacket layer (52); and e. stretchingunder heat the strength-member jacket layer (52) and the elongatableinternally-located conductive structure followed by cooling both theelongatable internally-located conductive structure as well as thestrength member jacket layer (52), while maintaining a tension needed toretain the elongated headline sonar cable at a determined amount ofelongation from its initial length, thereby permanently lengthening theheadline sonar cable a predetermined amount while simultaneously notbreaking or causing to become brittle the conductor.
 198. The method ofclaim 197 further comprising an additional step of selecting to form thefirst strength member (14) with a different mass of material incomparison with a mass of material selected for forming the braidedstrength member jacket layer (52).
 199. The method of claim 198 furthercomprising an additional step of selecting for the material mass of thefirst strength member (14) a material mass that is lesser than thematerial mass of the braided strength member jacket layer (52).
 200. Themethod of claim 199 where the step of coupling the combination of theelectrical energy conductor (122) and the first strength member (14) tothe layer of thermoplastic material further comprises enclosing thecombination of the electrical energy conductor (122) that is coupled tothe first strength member (14) within the layer of thermoplasticmaterial.
 201. The method of claim 199 further comprising selecting toform the electrical conductor (122) at the moment it is being coupled tothe first strength member (14).
 202. The method of claim 201 furthercomprising an additional step of selecting to form the conductor (122)by braiding the conductor (122) about the first strength member (14).203. The method of claim 202 further comprising an additional step ofselecting a braid angle when forming the braided conductor that is moreobtuse in comparison to a braid angle selected for the initial formationwith a braiding machine of the strength-member jacket layer (52). 204.The method of claim 200 further comprising extruding and/or pultrudingthe layer of thermoplastic material about the combination of theelectrical energy conductor (122) coupled to the first strength member(14) prior to forming the strength-member jacket layer (52).
 205. Themethod of claim 199 further comprising additional steps of forming ashielding layer (36) of electrically conductive material around thelayer of thermoplastic material prior to forming the strength-memberjacket layer (52).
 206. The method of claim 205 further comprisingselecting to form another layer of thermoplastic material about theshielding layer (36) of electrically conductive material, prior toforming the strength-member jacket layer (52).
 207. The method of claim206 further comprising forming about the another layer of thermoplasticmaterial a sheath of tightly braided fibers and/or filaments having ahigher softening point than the softening point of the another layer ofthermoplastic material, prior to forming the strength-member jacketlayer (52).
 208. The method of claim 207 further comprising additionalsteps of selecting to situate between the another layer of thermoplasticmaterial and the sheath of tightly braided fibers and/or filaments froma minimum of at least one fiber optic conductor (22) to several fiberoptic conductors prior to forming the strength-member jacket layer (52)by wrapping from at least one to several fiber optic conductors inspiral form about the another layer of thermoplastic material in such afashion so as to ensure sufficient slack in the at least one fiber opticconductor (22) so that it does not break during the stretching of thestrength member jacket layer (52).
 209. The method of claim 208 furthercomprising steps of selecting to situate additional thermoplasticmaterial so as to fill in at least some of and preferably most of and/orall of void spaces (97, 98) existing between the another layer ofthermoplastic material; the sheath of tightly braided fibers and/orfilaments; and the at least one fiber optic conductor (22).
 210. Themethod of claim 199 wherein, at least prior to the step of permanentlyelongating the strength member jacket layer (52, the method furthercomprises an additional step of selecting to form the at least a firststrength member (14) with a potential for constructional elongation at10° C. that is different in comparison to a potential for constructionalelongation at 10° C. of the conductor (122).
 211. The method of claim199 further comprising an additional step of selecting to form the firststrength member (14) so that it requires more tension to elongate itbeyond two percent stretch in comparison to a tension required toelongate the conductor (122) the same certain amount.
 212. The method ofclaim 205 further comprising selecting to employ the shielding layer(36) formed of electrically conductive material as another conductor,including so as to form a conductive loop employing the shielding layer(36) and the braided conductor (122).
 213. The method of claim 205further comprising additional steps of selecting to situate from atleast one to several fiber optic conductors between at least thestrength-member jacket layer (52) and the shielding layer (36).
 214. Themethod of claim 208 further comprising selecting to employ the shieldinglayer as the output loop of a first conductive loop while employing theconductor (122) as the input loop of the first conductive loop, whileemploying at least one fiber optic conductor as another input leg. 215.The method of claim 199 further comprising an additional step ofselecting for the first strength member (14) a strength member having abreaking strength that is between two hundred fifty grams to sixteenhundred kilograms while selecting a breaking strength for the strengthmember jacket layer (52) that is at least four thousand kilograms up tofour million kilograms.
 216. The method of claim 199 further comprisingan additional step of selecting to form the first strength member (14)with a different diameter and/or width in comparison with a diameterand/or width selected for forming the braided strength member jacketlayer (52).
 217. The method of claim 216 further comprising anadditional step of selecting for the diameter and/or width of the firststrength member (14) a diameter and/or width that is lesser than thediameter and/or width of the braided strength member jacket layer (52).218. The method of claim 217 wherein, at least prior to the step ofpermanently elongating the strength member jacket layer (52), the methodfurther comprises an additional step of selecting to form the strengthmember jacket layer (52) with an ability to elongate at temperatureslesser than fifty degrees Celsius that is different in comparison to anability to elongate of the first strength member (14) at temperatureslesser than 50° C.
 219. The method of claim 217 further comprising anadditional step of selecting for the first strength member (14) astrength member having a breaking strength that is between seventythousand to twenty times lesser than the breaking strength of thestrength member jacket, layer (52).
 220. The method of claim 217 furthercomprising an additional step of selecting to stretch the strengthmember jacket layer (52) to an extent that causes the first strengthmember (14) to experience failure.
 221. The method of claim 217 furthercomprising an additional step of selecting to stretch the strengthmember jacket layer (52) to an extent that causes the first strengthmember (14) to break.